For a plasma etching apparatus, a plasma CVD (chemical vapor deposition) apparatus and the like that are used for manufacturing a semiconductor device, a fluorine-based elastomer excellent in heat resistance and plasma resistance among elastomers has been used as a seal material for maintaining a process chamber in which a semiconductor wafer is treated vacuum.
At a gate part that separates a process chamber and a transfer chamber of the plasma etching apparatus, the plasma CVD apparatus and the like, a gate valve having a seal structure body in which a seal material is attached to a metallic support is provided, and transfer and treatment of the semiconductor wafer are repeated by opening and closing the gate valve.
Among gate valves, there is a gate valve of a seal material engaging type, in which a groove is formed on a metallic support such as aluminum and a seal material is fitted into the groove. The gate valve of the seal material engaging type has problems of torsion of the seal material, falling of the seal material from the groove, and the like. Accordingly, a gate valve of a seal material adhesion type where a seal material is adhered to a metallic support is suitably used. For the gate valve of the seal material adhesion type, an adhesive composition having a high adhesive property between the metallic support and the seal material is required to be capable of withstanding the repeated opening and closing.
In particular, when a perfluoroelastomer (FFKM) that has the highest heat resistance and plasma resistance among fluorine-based elastomers is used as a seal material, the perfluoroelastomer has a poor adhesive property with a metallic support since carbon atoms of side chains constituting the perfluoroelastomer are fully fluorinated. Accordingly, an adhesive composition having a high adhesive property between the metallic support and the perfluoroelastomer that is the seal material is required.
As an adhesive composition that causes a perfluoroelastomer that is an organic material to adhere to a metallic support that is an inorganic material, a coupling agent such as a silane coupling agent has been known. However, it is difficult to increase the adhesive property between the metallic support and the perfluoroelastomer only by the silane coupling agent.
Then, Japanese Patent Laying-Open No. 2007-277340 (PTD 1) discloses, as an adhesive composition having a high adhesive property between a metallic support and a perfluoroelastomer, a vulcanizing adhesive composition obtained by compounding 50 to 400 parts by weight of a silane coupling agent and 50 to 400 parts by weight of an organometallic compound to 100 parts by weight of a phenolic resin.
In addition. International Publication No. WO 2011/071984 (PTD 2) discloses, as an adhesive composition having a high adhesive property between a metallic support and a perfluoroelastomer, a primer composition including a curative, a solvent and an epoxy resin; wherein the curative is capable of reacting with the epoxy resin; and further wherein; (a) the curative is capable of curing a perfluoroelastomer compound having at least one curing site and a crosslinking agent or catalyst; or (b) when the curative is not capable of curing the perfluoroelastomer compound, the perfluoroelastomer includes a crosslinking agent or catalyst capable of curing the epoxy resin.